Split transaction mod to multi files mod.

[liurenjie1024]

As we are adding more and more transaction actions, the transaction module will become too large to maintain. We need to convert it to multi file module to make it easier to maintain.

[jonathanc-n]

I can work on this!

[liurenjie1024]

I can work on this!

Thanks!

[jonathanc-n]

I'll work on this after #960 gets merged.